New Zealand won a Test series against South Africa for the first time with Kane Williamson hitting an unbeaten century Friday to steer them to a seven-wicket victory in the second Test.

Williamson's unbeaten 133 was at the heart of their 269-3 in the fourth innings of a tight Test in Hamilton to complete a 2-0 series win over the understrength tourists.

The Black Caps hadn't beaten the Proteas in 17 previous Test series dating back to 1931, having lost 13 and drawn four.

The 33-year-old Williamson was methodical throughout a 260-ball stay, putting on an unbroken stand of 152 with Will Young, who scored 60 not out, as New Zealand reached their target of 267 late on day four.

The in-form Williamson scored his seventh century in his last seven Tests, which included twin tons in the 281-run first Test victory at Mount Maunganui.

His 32 centuries have come from 172 innings, surpassing Australia's Steve Smith (174 innings) as the fastest player in Test history to reach that milestone.

Williamson batted through the day after New Zealand resumed at 40-1, adopting a disciplined approach on a tricky pitch, but was always prepared to punish loose deliveries, scoring 12 fours and two sixes.

New Zealand seamer Will O'Rourke finished with nine wickets on his Test debut to earn the man-of-the-match award with Williamson named player of the series.

New Zealand briefly wobbled when opener Tom Latham was dismissed in the first session for 30 and Rachin Ravindra soon after lunch for 20, but Young dug in to reach his seventh half-century.

The inexperienced Proteas struggled to make an impact aside from Dane Piedt, who finished with 3-93 to give him eight scalps in his first Test in more than four years.

Offspinner Piedt struck early by removing Latham, the opener caught by Zubayr Hamza driving to short cover after adding nine to his overnight score.

Ravindra was undone by a near-identical shot after New Zealand had resumed the second session at 107-2.

South Africa were fielding a side missing the majority of their first-choice players, who skipped the series to instead contest their lucrative domestic Twenty20 league.